Hall said: "He has been let down by his own inexperience and the inexperience of others. There were also a series of extremely poor appointments stemming from the fact Mike inherited Sam Allardyce. And, no, I don't blame him for getting rid of Allardyce because the football was the worst we had ever seen.
"Then he listened to the fans and brought Keegan back. And that was a mistake. You can never re-tread footsteps in business. Life and circumstances change, the world and the game moves on. You have to have fresh blood.
"One mistake led to another with Dennis Wise and Joe Kinnear coming on board. Two terrible appointments. Wise was trying to do the job from London and that was ridiculous.
"You have to be up here, getting to know the people and their feelings for the club. There was obviously bad blood between Keegan and Wise which I'm told went back to their England days. It was like a red rag to a bull.
"As for Kinnear, you have to have people who are active in the game.
"Now it's all gone wrong and Mike has to decide whether to stay or sell up - and, believe me, there are always people around who want to buy clubs like Newcastle.
"If he stays he has to inject new funds. Not once but twice.
"First, to build a new team to fight their way out of the Championship, then to stay up. I know from my experience with Kevin that you have to have real battlers to get back into the Premier League.
"On top of that, it's obvious they are going to struggle to attract the top quality players.
"But I don't go along with the feeling Newcastle could become another Leeds or Nottingham Forest and end up in League One.
"We're too strong for that. Yes, there's a huge wage bill and that has to be trimmed. And there must be no uncertainty in the close season. The club has to get on with it."